Ryzom

You can follow the part with "jom" :) That's a nmake clone created by Nokia for compiling with all cores (it supports the -j <cores> parameter and uses all cores by default).

This justifies jom...
... but was that the reason to use jom in the first place?

Hum, jom is marked "optional", I don't see what you mean.

...well... put it like this:

To easily use multicore for building would have been a very good reason.
But your comment sounds as if that wasn't the case.

What for did you include (or use) jom anyway, if you could have used nmake in the first place?

Ok, i installed and used JOM: ftp://ftp.qt.nokia.com/jom/jom100.zip
It was fairly easy to install, the instruction on the wiki says it all.
Instead of the recommended one, i used the newest build of JOM as well - ftp://ftp.qt.nokia.com/jom/ - and i added the link to the wiki.
JOM does in fact speed up bulding and compiling from the commandline decisively, compared to nmake.
It still is a bit slower that using the visual studio gui, but it still is worth the (neglectable) trouble, as you still save time.
I'd recommend the commandline for building of releases on windows.
I'd still recommend using visual studio/vc++ express for debugging, as in that case the compiler uses incremental building, which is still faster even with single core than full build with multi-core (at least it was for me).
Fair warning: I still can't say if there are caveats in the result, that is, in the binaries, as there are warnings galore on the commandline, nmake or not.
I just hope it works... ;)